Wall duct



FIG. 1 is a front perspective view of a wall duct;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is an elevation view as viewed from the left side thereof;

FIG. 5 is an elevation view as viewed from the right side thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

The broken line showing of the wall duct is for the purpose of illustrating portions of the wall duct and forms no part of the claimed design. 

CLAIM The ornamental design for a wall duct, as shown and described. 